Electrical measuring instrument



March 19, 1929. E M 1,705,682

ELECTRICAL mmsumwe msmumsm' I Filed June '4, 192'! WITNESSES: lNVENTOR fidm Georg Reime Patented I i-lain 19, 1 929.

unites niincrzercar. MEASURING INSTRUMENT.

Application filed June 4, 1927, Serial No. 196,425, and in Germany July 7, 1926.

My invention relates to electrical meas I urin instruments and more )articularl to direct current ampere-hour metersi An object of my invention-is, to provide;

means for ample steel magnets having a high coercive force in meters.-

Another object of my invention is toprovide means for reducing the size and weight of meters to a minimum.

A further object-of my invention is toprovide relatively simple adjustable'mounting means for magnets. p 7

These and other, useful and desirable ob.- jects will be more. fully explained inthe accompanying description. v

The size and weight of meters 'may b-e considerably reduced by the use of magnet steels, such as cobalt, having a high coercive force but suchv steels have a serious disadvantage in that they have a tendency to crack in the bending. and drilling operations, thus rendering the manufacture of such steels for meters very expensiv'ej Therefore, in order to reduce the cost of 'inanufacture to a minimum, it is necessary that the shape of the magnets be as simple as possible.

In practicing my invention 1 provide novel" mounting means so that an especially simple shapeof hard steel magnet, for example cobalt'steel maybe used for. meters such as direct current ampere hour meters.

In accordance withn'iy invention a plurality of barmagnets made of steel having a high coercive force are disposed on both sides of a disc armature. -T'he bar magnets are mounted in a frame surrounding the armature in such manner that they are normally parallel to each other and parallel to the plane of the armature, but vmains are provided for adjusting the position of the bar magnets if it becomesnecessary.

T he ends of the bar magnets are disposed with poles of different polarity opposite each other. The magnetic lines of force leaving one pole, therefore .traversethe' disc and then enter the opposite pole.

In a modification of my invention the ends of the bar magnets are connected by a clamp to the frame, having a portion or the clamp next to the dlsc constructed of a magnetic material so that it constitutes the pole shoe ward d rection and'the screws 1n the lower of the magnet.

meter-showniin ig. 1;

My invention may be better understood if the accompanying drawings are taken in, con-i nection with the following description.

Figure 1 is a viewin elevation of a por- PFATEM fi m-1.

. ozone Lamina, oriuunmuenne, GER ANY, ASSIGHOR 'ro wnscrrucnousu ELECTRIC:

tion of an ampere-hour meter constructed in accordance with my invention;-

Fig. 2 is a view in side elevation of the Fi 3 is a View, in section, of the meter shown in F1g..1, taken on the line III,.III,

and

Fig. 4 is a view similar to Fig. 3 ofa modilication of my invention.

An ampere-hour meter constructed in accordance with my inventionycomprises, in,

general, a frame '1 having inwardly extend.-

ing projections 2 and-13, adapted to support A an upper bearing 4 and alower bearing 5. An armature disc 6 mounted-on aispindle 7 is adapted to rotate between the upper bearing '4 and the lower bearing 5. The frame 1 is mounted in the inner portion of a casing (not shown) by means of machine screws 8.

Current is lead into, and-outo-f, the arnature circuit by means of brushes 9 a-nd'10 mounted respectively on supportingmembers- Hand 12, that are in turn secured to the frame 1..

The frame 1 is provided with inwardly err-- tending projections ,14 and 15 on 'whicha're 16 comprises a bottom clamping member 18 and a top clamping member 19. The bottom recess for the ends ofbar magnets 20 and mounted clamps 16 -and 17. The upper clamp v 21. A screw 22 adj ustably secures the bottom 7 member 18 to the projection .14 of the frame 1. Two. screws 23 and 24 are disposed. in the projection member 14 on opposite sides of the screw 22. The screw 22 tends to pull the lower clamping member 18 upwardly and the screws 23 and 24 tend to push the'top clamping member 19 downwardly so that theends of the bar magnets20 and 21 are held firmly between thetop clamping member 19 and the bottom clamping member 18.

Therlower clamping assembly 17 1s constructed in a manner similar to the construe tion of the upper clamping assembly 16, with the exception, of course, that the screw in the lower member corresponding to the screw22' in the upper member, tends to pull in a downassembly 17 corresponding to the screws 23 and 2a in the upper; assembly 16 tend to push upwardly.

The frame 1 is provided with sides 25 and 26 that surround the edge of the armature 6 and are bent tangentially thereto in order to effect a reduction in the size of the casing and also to strengthen the frame 1.

The bar magnets are of extended prismatic form and are free from any drill holes or any other reductions or weakness in the cross section, and can, therefore, be easily manufactured. The lower clamping members in the upper clamping structures, and the upper clamping members in the lower clamping structures are of a magnetic material and,

comprise pole shoes for the cobalt steel bar magnets. The threaded screw means for securing the clamping structures to the frame,

' make possible a very easy regulation of the field strength between the pole shoes and secures the bar magnets so firmly to the frame structure that they will not be moved from their position b the magnetic pull that takes place between t iem.

The frame 1 and the clamping members are constructed in such a manner that the cobalt steel bar magnets are symn'ietrically disposed on both sides of the armature.

In a modification of my invention shown in Fig. 4:, single bar n'lagnets 20 are mounted on both sides of the armature 6 and are adapted to extend angularly to the plane of the frame 1. Frame 1 is provided with an inwardly extending projection 27'and an outwardly extending projection 28. The bar magnets 20 v are secured directly to the projections 27 and 28 by means of the screws 29. The pole shoes 30 are secured to the projections 27 and 28 by the screws 31. The adjustable screws are I adapted to engage the surface of the pole shoes 30 in such manner that angular motion of the A meter constructed in accordance with my invention has also a distinct advantage, in that the essential operating parts of the meter may be readily and efficiently adjusted by the threaded screw clamping means that hold the cobalt magnets in position. The loss in manufacture caused by the cracking and bending of sections of cobalt steel is entirely eliminated because the sections'are made in the simplest form or shape possible.

My invention may be variously modified without departing from the spirit thereof, and I desire to include all such modifications within the scope of the appended claims.

I claim as my invention:

1. The combination with the armature of a meter, of means for damping rotation thereof comprising a plurality of magnetized bars disposed symmetrically on opposite sides of said armature.

2. In combination, a disc armature, a plurality of bars of magnetized cobalt steel and means for adjustably mounting saidbars in pairs on opposite sides of said disc.

3. The combination with the armature of a meter, of means for damping movement therein, comprising a plurality of unbent magnetized bars disposed on opposite sides of said armature.

In testimony whereof, I have hereunto subscribed my name this 27 day of April, 1927.

.GEORG REIME, 

